“A full bus can take 40 cars off the road.”
Carbon Emissions from Transport
Road transport contributes almost 15 per cent of total green house gas emissions in Australia. Cars contribute almost 50 per cent of road transport related emissions.
By 2020 greenhouse gas emissions from road transport are predicted to be more than two thirds higher than their 1990 levels with cars still accounting for the majority.
Figure 1: Greenhouse Gas Emissions Growth for Road Transport
Reducing Carbon Emissions from Transport
Shifting from cars to public transport can deliver a 65 per cent emissions reduction during peak times and a 95 per cent reduction in emissions during off peak times from the commuters that make the shift.
Transport greenhouse gas emissions can be reduced by
At current occupancy rates for cars a full bus load of passengers can take more than 40 cars off the road and a full passenger train can take 500 cars off the road.
Based on 2004 occupancy figures for cars and buses the fuel consumption of buses for every 100 passenger kilometres was 2.5 litres and the fuel consumption of cars for every 100 passenger kilometres was 7 litres.
A ten per cent shift to bus passenger transport from cars would reduce greenhouse gas emissions by more than 400,000 tonnes a year and every million passenger kilometres on public transport, instead of cars, saves 45,000 litres of fuel. 
The emissions savings figures for trains, if extrapolated from the figures delivered for bus by CRA international suggest a ten per cent shift to rail passenger transport from cars could save as much as 4Mt of emissions a year. 
In the long term reduced dependency on cars will lead to further reductions in emissions from road transport.
BIC sees six key ways by which road transport GHG emissions can be reduced to achieve these targets, and the six could be utilised in many different ways to achieve targets, as illustrated in the following table (options A, B and C all meet the 2020 target):
Table 1: The efficacy of different measures and targets in achieving reductions in road transport greenhouse gas emissions.
All the sets of measures set out in the table will require major behavioural and technological changes, particularly early action to redress the lack of progress over the nearly two decades since 1990 – which reflects badly on transport policy and planning skills and processes in Australia.
The required changes can be summarised in the following 9 key actions:
BIC believes that these are all quite feasible within the 2020 timeframe, provided we act quickly.
The 2050 targets are far more problematic and BIC doubts whether road transport GHG emission reductions of about 80% on 2000 levels by 2050 are achievable, unless there are major break-throughs on vehicle fuel economy (delivering reductions of about 90% on current vehicular GHG emission rates).
The upcoming emissions trading scheme is unlikely to deliver substantial emissions reductions from road transport, given low fuel price elasticities and strong underlying growth in transport demand. Complementary substantial investments and policy interventions will also be required to change the very nature of our cities, transport systems and travel behaviour to make significant road transport emission reductions.
Our research indicates that achieving very substantial reductions in vehicle emission intensity is absolutely vital to making major inroads in road transport GHG emissions. We believe that this will require mandatory GHG emission standards and a focus on changing consumer behaviour towards purchase of less emission intensive vehicles.
Many of the emission reduction initiatives considered in this report will benefit from urban development policies and plans that facilitate more compact urban settlement patterns. Such urban design will help to reduce travel distances (e.g. because of closer proximity of trip origins and destinations), make walking and cycling easier and improve the economics of public transport service provision.
Analysis of the equity implications of carbon pricing/emissions trading suggests that this will have regressive distributional impacts. By carefully framing the complementary emission reduction measures outlined in this report, the travel needs of disadvantaged people can be given high priority, to help to mitigate these regressive impacts. Bus service improvements in outer suburbs of Australian cities and regional areas will be central to this approach.
 Barrett and Stanley (2008), Moving People: Solutions for a Growing Australia, ARA, BIC, UITP
 Bureau of Infrastructure, Transport and Regional Economics, 2010, Long Term Projections of Australian Transport Emissions, Report for the Department of Climate Change and Energy Efficiency, Canberra.